In hazardous chemical accidents, immediate identification of composition, content, and distribution of hazardous chemicals is important to promptly and effectively implement emergency response and procedure. The vibration frequencies or rotation frequencies of organic molecules contained in common hazardous chemicals are in terahertz band (0.1 THz to 10 THz), where the molecules exhibit strong spectral fingerprint characteristics. Therefore, terahertz spectroscopy technology has a significant practical application in detecting hazardous chemicals in the air.
A bandwidth of the entire terahertz spectral detection system should be above 1 THz to identify multiple components. However, in conventional terahertz source technology, the bandwidth of a single frequency point is tens to hundreds GHz. Moreover, the power of the terahertz source is very weak, generally only a few milliwatts.